import React, { Component } from 'react'
import './index.css'

export default class Footer extends Component {

    // 全选checkbox的回调
    handleCheckAll = (event)=>{
        this.props.checkAllTodo(event.target.checked)
    }

    // 清除所有已完成任务的回调
    handleClearAllDone = () =>{
        this.props.clearAllDone()
    }

    render() {
        const {todos} = this.props
        // 已完成的个数
        const doneCount = todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0),0)
        // 总数
        const total = todos.length
        return (
            <div>
                <div className="todo-footer">
                    <label>
                    <input type="checkbox" onChange={this.handleCheckAll} checked={doneCount === total && total !== 0 ?true:false}/>
                    </label>
                    <span>
                    <span>已完成{doneCount}</span> / 全部{total}
                    </span>
                    <button className="btn btn-danger" onClick={this.handleClearAllDone}>清除已完成任务</button>
                </div>
            </div>
        )
    }
}
